A BIOSENSOR FOR FERRIC ION

A new biosensor for monitoring iron has been developed. The active sol id phase is pyoverdin, a natural fluorescent pigment biosynthesized by Pseudomonas fluorescens immobilized on controlled pore glass (CPG) an d packed in a quartz flow-through cell. The biosensor is very selectiv e for iron(III) and can be easily regenerated in about 2 min by passin g IM HCl through the cell. The optimum conditions and analytical chara cteristics (detection limit, precision and linear range) for the new s ensor in solution (DL = 10 ng/ml) and in immobilized form (DL = 3 ng/m l) are reported. The biosensor has good stability and can be used cont inuously over a period for at least 3 months (over 1000 determinations ). The sensor was successfully applied to determine iron in different water samples. There were no significant differences between the new m ethod and the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) reference method at the 95% confidence level.